Page 1 of 2
If only 2001's sounded like this...
Posted: Sun Jun 22, 2008 9:47 am
by ver tum
I'd like to give special thanks to Siren1000T for giving me permission to use the audio from his 2001-DC video for this. I was messing around with Audacity, and this was the final product.
http://www.youtube.com/watch?v=Wjl4MtvDcnU
Posted: Sun Jun 22, 2008 1:23 pm
by SirenMaster2000
Cool. Sounds like a fusion of a 2001 and an XT22.
Posted: Sun Jun 22, 2008 3:06 pm
by Jim Z
if I may ask, how did you grab the audio?
Posted: Sun Jun 22, 2008 3:46 pm
by SirenMadness
That sounds great! Even though the geometry of a two-tone stator would make the design only decent, that would be a hell of a siren.
Posted: Sun Jun 22, 2008 4:24 pm
by JasonC
Wow, that does sound nice! Unfotunatley, Federal would loose 3+ dB (if not more) if they switched to this design.
Posted: Sun Jun 22, 2008 5:27 pm
by Jim Z
Wow, that does sound nice! Unfotunatley, Federal would loose 3+ dB (if not more) if they switched to this design.
Due to destructive interference, or smaller chopper/stator ports?
Posted: Sun Jun 22, 2008 5:57 pm
by JasonC
Jim Z wrote:
Due to destructive interference, or smaller chopper/stator ports?
Smaller ports have a lot to do with it and also due to the fact that dual tone choppers are inefficient designs since they cannot compress the air as much. A single tone rotor spends 50% of its time compressing the air, and 50% releasing it. Dual tone rotors average much less compressing time.
IOW, as the rotor is spinning, it can't develop as much pressure because there are to many holes out of alignment.
Posted: Sun Jun 22, 2008 10:41 pm
by ver tum
Jim Z wrote:if I may ask, how did you grab the audio?
I just used Audacity to capture the audio from the stereo mix on my sound card. I exported it as a WAV file, imported the WAV file on to two tracks, and changed the pitch of the second track -3.125 semitones. I really didn't think it would turn out as good as it did, but after I heard that xT22-like sound, I asked Dan (Siren 1000T's permission to post it here and on YouTube, and he gave me the ok.
I know that this would call for a complete redesign of the 2001, but wouldn't a small DC powered blower make up for the 3 or so DB lost when using a duel tone rotor? If I ever get my hands on a 2001 some day, I'd love to experiment with it.
Posted: Sun Jun 22, 2008 11:17 pm
by JasonC
ver tum wrote:
I know that this would call for a complete redesign of the 2001, but wouldn't a small DC powered blower make up for the 3 or so DB lost when using a duel tone rotor? If I ever get my hands on a 2001 some day, I'd love to experiment with it.
It would require a blower equal to about 100hp to supply enough air to the 2001. That would defeat the purpose of the 2001's simple design.
Posted: Mon Jun 23, 2008 7:37 am
by ver tum
I didn't think that a 100 HP blower would be needed just to increase the sound output by 3 DB.